Electrical apparatus



July 18, 1933- A. M. PoNlAToFF ELECTRICAL APPARATUS Filed Feb. 7, 1930 In Venter:

Patented July 18, 1933 LlQM ALEXANDER IVI. PONIATOFF, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T GENERAL FLECTR- COMPANY, A CORPORATION 0F NEW YORK ELECTRECAL APPARATUS Application filed February 7,

My invention relates to electrical apparatus, and more particularly to conductor studs adapted to extend through a casing or housing for transmitting comparatively large currents.

It is an object of my invention to provide an improved conductor stud which shall have means for effectively dissipating the heat generated within the stud by currents traversing the same, and which shall be simple, rugged, and economical in construction.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be point-ed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, l is an elevational view, partly in section, of a fluidbreak circuit interrupter embodying my invention` and Fig. 2 is a fragmentary detail view, partly in section, of parts illustrated in Fig. 1.

In Fig. 1 there is shown by way of example, a. housing 1 containing a circuit interrupter of the Huid-break tvpe7 It shall be understood, however, at this point that the housing l may contain a transformer structure. or any other electrical apparatus which is to be connected with exterior lead conductors by a conductor stud through a wall of the housing. In the present instance, the hollow conductor stud 2 of copper which er-- tends through the upper wall of the housing l is mounted within an insulating bushing 3 of suitable insulating material which is, in turn, mounted within and supported by a Hange orcollar 4. The collar 4 which engages at its inner periphery an annular shoulder 5 formed in the insulating bushing, is secured, as by the bolts 6, to the upper wall of tle housing l, and comprises a depending tubular portion 4.

The upper portion of the conductor stud comprises a retaining shoulder 7 for engaging the upper end of the insulatingl bushing. and a pair of plate-like extensions 8 formed by cutting a V-notch in that end of the conductor stud and flattening out the opposite 1930. Serial No, 426,677.

sides of the conductor so that they are substantially parallel with each other, as illustrated in Fig. 2. Apertures 8 are drilled through the extensions or clamping portions 8 in order that the conductor stud may be 55 electrically connected to the terminal portion of a lead conductor by bolts, rivets, or the like. The opposite or lower end of the conductor stud is likewise slotted and shaped to form a pair of plateor flange-like por- '6G tions 9, to which is electrically connected the stationary contact structure 10 of the switch. The conductor stud is externally screw threaded at its lower end, as at 11, and receives a pair ot clamping and retaining nuts M2 l2 for securing` in position the insulating shield 1.3, and for engaging the lower end of the insulating bushing 3. A cylinder 14 of suitable insulating material coveringr and strengthening the lower portion of the insulating bushing is maintained in position by the shield 13 and the depending tubular extension 4 of the collar Il. The lower portion of the `conductor stud, including the shield L3 and the stationary contact structure l0, is 75 immersed within an insulating fluid 15, such as oil., which serves to quench the arc formed during separation or downward movement of the bridging Contact 16 from the stationary. contact 10. It is of course apparent that the 50 lower portion of the conductor stud may be suitably modilied to connect with transformer structure or other electrical apparatus.

The tubular conductor stud when applied to both circuit breakers and transformers, permits not only a more simplified construction but results in increased efticiency and capacity of the electrical apparatus. In other words.,v the connecting unions between the conductor stud and other apparatus which are known as adapters may be entirely eliminated. Since it has been customary to use adapters of cast copper. the conductivity of which is about 80% that of worked copper, it will be apparent that the conductivity of the connection constructed in accordance with my invention is increased and that the cost ot construction and the amount of material used is decreased. The simplified construction of the hollow conductor stud serves 0C to increase the capacity of the electrical apparatus since the high effective resistance caused by the well known skin eHect in the solid conductor is not so pronounced, the permissible current density per square inch of material for the same temperature rise being nearly twice that ot a solid conductor stud.

In the construction so far described, the passage of large. power currents through the conductor stud and switch contact structure results in the generation of considerable heat within the stud due to the high effective resistance caused by the well lrnown skin effeet, and the insulating bushing 3, which is in general a poor conductor of heat and tends to further increase the effective resistance of the conductor stud. To the end that the heat so generated shall not accumulate to increase the temperature of the conductor stud and insulating bushing to a dangerous extent, there is provided means for establishing automatic circulation of air from the exterior through the entire length of the conductor stud, thereby removing excess of heat and maintaining the conductor stud comparatively cool. For this purpose, the lower end of the conductor stud is provided with a deliecting plug or stop member 17 composed of material such as brass and having a conical defiecting surface 18. Mounted within and extending longitudinally oli' the conductor stud is a tubular member 19 open at its lower end and spaced a short distance from the dellecting member 17. The diameter of the tubular member 19 is less than the internal diameter of the conductor stud so that approximately equal volumes ot' air may flow interiorly and exteriorly of the tubular member. Member 19 is provided at its upper end With a pair of horizontally extending tubes 20 open at their opposite ends so as to place the member 19 in communication with the atmosphere at opposite sides of the conductor stud. As more clearly illustrated in Fig. 2, the tubes 20, which form with the member 19 a T-shaped structure, rest within and in the present instance overhang the notches formed in the conductor stud so as to be supported therein. When inserted through the upper end of the conductor stud and permitted to rest in the position illustrated in Fig. 2, the T-shaped tubular structure is in operative position, the lower end of the tubular member 19 being equally spaced from the inner Wall of the conductor stud by spacing members 21.

`Assuming now that heat is being generated within the conductor stud by large currents traversing the same, the air within the space between the tubular member 19 and the conductor stud rapidly becomes heated so that 1t tends to ascend to the exterior of the stud to the atmosphere. When this movement of air takes place, there is simultaneously set up a current of cooler air from the atmosphere in the direction of the arrows through the oppositely extending tubes 20, downwardly through the tubular member 19, the current being reversed by the detlccting member 17, as indicated, so as to ascend within the ever the temperature rises within the stud and increases to apredetermined extent. The horizontal or intake tubes of the cooling structure are so located that there will be very little mingling, if any, of the ascending heated air with the cooling air which flows laterally into the intake tubes. Accordingly, the circulation of air will be quite positive due to the fact that the cool air may flow into the system Without resistance of any kind.

It shall be understood that my invention is not limited to the specific details of construction and arrangement thereof herein illustrated, and that various changes and modifications will occur to those skilled in the art, Without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In electrical apparatus comprising a iousing, an insulated conductor extending through a wall of said housing comprising a hollow conductor stud, an insulating bushl ing for mounting said stud with respect to the housing, and means for establishing circulation of cooling air through the interior.

of the stud upon heating thereof comprising a tubular member extending within and longitudinally of said stud, and horizontally disposed intake tubes communicating with the tubular member and forming therewithl a T-shaped structure, the openings of the intake tubes being located adjacent the upper opening of the conductor stud and out of the path of heated air currents flowing therefrom.

2. An electrical conductor for transmitting comparatively large currents comprising a hollow stud, said stud having a V-shaped slot at one end thereof, and clamping flanges formed by the material of the stud on opposite sides of said slot.

3. An electrical conductor comprising a hollow stud, said stud being notched at its opposite ends, and a pair of clamping ilanges formed by the material of the stud at opposite sides of each notch for electrically connecting the conductor to a lead conductor and switch contact structure respectively.

4. A self-cooling, insulated conductor comprising a hollow conductor stud, said stud being slotted at its Lipper open end, a tubular member extending within and longitudinally of the stud for guiding the passage of cooling air into and out of the stud to dissipate heat generated therein, and horizontally disposed tinuous air passage between the interior of said tubular member and the annular space between the same and said stud, and an air intake for said tubular member comprising a horizontally dlisposed tube overhanging and extending beyond the open end of said stud` said tubular member being otherwise closed at its upper end so that exhaust of heated air upwardly through the aforesaid annular passage in said stud causes flow of cooling air through said intake tube and downwardh7 into the interior of said stud.

ALEXANDER M. PoNIAToFF. 

